[PATCH v3 5/9] drm/bridge: synopsys: dw-mipi-dsi: Use pixel clock rate to calculate lbcc

[Liu Ying]

To get better accuration, use pixel clock rate to calculate lbcc instead of
lane_mbps since the pixel clock rate is in KHz while lane_mbps is in MHz.
Without this, distorted image can be seen on a HDMI monitor connected with
i.MX93 11x11 EVK through ADV7535 DSI to HDMI bridge in 1920x1080p@60 video
mode.

Signed-off-by: Liu Ying <victor....@nxp.com>
Reviewed-by: Neil Armstrong <neil.armstr...@linaro.org>
---
v2->v3:
* Add Neil's R-b tag from v1.

v1->v2:
* No change.

 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index c754d55f71d1..332388fd86da 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -12,6 +12,7 @@
 #include <linux/component.h>
 #include <linux/debugfs.h>
 #include <linux/iopoll.h>
+#include <linux/math64.h>
 #include <linux/media-bus-format.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -762,8 +763,15 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct 
dw_mipi_dsi *dsi,
                                           u32 hcomponent)
 {
        u32 frac, lbcc;
+       int bpp;
 
-       lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+       bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+       if (bpp < 0) {
+               dev_err(dsi->dev, "failed to get bpp\n");
+               return 0;
+       }
+
+       lbcc = div_u64((u64)hcomponent * mode->clock * bpp, dsi->lanes * 8);
 
        frac = lbcc % mode->clock;
        lbcc = lbcc / mode->clock;
-- 
2.37.1